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Namespaces allow you to use Anyquery as a library rather than a CLI. Create a namespace, load some plugins and be handed back a sql.DB pointer. Under the hood, it's simply a wrapper around go-sqlite3 and the virtual tables of anyquery.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,243 @@ | ||
| package namespace | ||
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| import ( | ||
| "database/sql" | ||
| "errors" | ||
| "math/rand/v2" | ||
| "strconv" | ||
| "strings" | ||
|
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| "github.com/julien040/anyquery/module" | ||
| "github.com/julien040/anyquery/rpc" | ||
| "github.com/mattn/go-sqlite3" | ||
| ) | ||
|
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| type NamespaceConfig struct { | ||
| // If InMemory is set to true, the SQLite database will only be stored in memory | ||
| InMemory bool | ||
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| // The path to the SQLite database to open | ||
| // | ||
| // If InMemory is set to true, this field will be ignored | ||
| Path string | ||
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| // The connection string to use to connect to the database | ||
| // | ||
| // If set, InMemory and Path will be ignored | ||
| ConnectionString string | ||
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| // The page cache size in kilobytes | ||
| // | ||
| // By default, it is set to 50000 KB (50 MB) | ||
| PageCacheSize int | ||
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| // Enforce foreign key constraints | ||
| EnforceForeignKeys bool | ||
| } | ||
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| type Namespace struct { | ||
| // Unexported fields | ||
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| // Check if the namespace was registered (the database/sql package was registered) | ||
| // If so, we cannot register any more plugins | ||
| // | ||
| // It's to prevent registering plugins that won't be used because the db connection is already opened | ||
| registered bool | ||
|
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| // The connection string to use to connect to SQLite | ||
| connectionString string | ||
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| // The list of plugins to load | ||
| goPluginToLoad []goPlugin | ||
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| // The list of shared objects to load | ||
| sharedObjectToLoad []sharedObjectExtension | ||
| } | ||
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| type sharedObjectExtension struct { | ||
| // Unexported fields | ||
| path string | ||
| entryPoint string | ||
| } | ||
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| type goPlugin struct { | ||
| // Unexported fields | ||
| plugin sqlite3.Module | ||
| name string | ||
| } | ||
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| func (n *Namespace) Init(config NamespaceConfig) error { | ||
| // Construct the connection string | ||
| connectionStringBuilder := strings.Builder{} | ||
| if config.ConnectionString != "" { | ||
| connectionStringBuilder.WriteString(config.ConnectionString) | ||
| } else { | ||
| if config.InMemory || config.Path == "" { | ||
| config.Path = "anyquery.db" // If in memory, we use a default path that will be ignored | ||
| } | ||
| connectionStringBuilder.WriteString("file:") | ||
| connectionStringBuilder.WriteString(config.Path) | ||
|
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| // Set shared cache to true | ||
| connectionStringBuilder.WriteString("?cache=shared") | ||
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| // Open the database in memory if needed | ||
| if config.InMemory { | ||
| connectionStringBuilder.WriteString("&mode=memory") | ||
| } | ||
|
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| // Set the page cache size | ||
| connectionStringBuilder.WriteString("&_cache_size=") | ||
| if config.PageCacheSize > 0 { | ||
| // To indicate a value in KB, we have to return a negative value | ||
| connectionStringBuilder.WriteString(strconv.Itoa((-1) * config.PageCacheSize)) | ||
| } else { | ||
| connectionStringBuilder.WriteString("-50000") | ||
| } | ||
|
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| // Set the journal mode to WAL and synchronous to NORMAL | ||
| connectionStringBuilder.WriteString("&_journal_mode=WAL") | ||
| connectionStringBuilder.WriteString("&_synchronous=NORMAL") | ||
|
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| // Set the foreign key constraints | ||
| if config.EnforceForeignKeys { | ||
| connectionStringBuilder.WriteString("&_foreign_keys=ON") | ||
| } else { | ||
| connectionStringBuilder.WriteString("&_foreign_keys=OFF") | ||
| } | ||
| } | ||
|
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| result := connectionStringBuilder.String() | ||
| n.connectionString = result | ||
|
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| return nil | ||
| } | ||
|
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| func NewNamespace(config NamespaceConfig) (*Namespace, error) { | ||
| n := &Namespace{} | ||
| err := n.Init(config) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| return n, nil | ||
| } | ||
|
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| // Load a plugin written in Go | ||
| // | ||
| // Note: the plugin will only be loaded once the namespace is registered | ||
| func (n *Namespace) LoadGoPlugin(plugin sqlite3.Module, name string) error { | ||
| if n.registered { | ||
| return errors.New("the namespace is already registered. Go plugin must be loaded before registering the namespace") | ||
| } | ||
| n.goPluginToLoad = append(n.goPluginToLoad, goPlugin{plugin: plugin, name: name}) | ||
| return nil | ||
| } | ||
|
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| // Load a SQLite extension built as a shared object (.so) | ||
| // | ||
| // Note: the plugin will only be loaded once the namespace is registered | ||
| func (n *Namespace) LoadSharedExtension(path string, entrypoint string) error { | ||
| /* if entrypoint == "" { | ||
| // https://www.sqlite.org/c3ref/load_extension.html#:~:text=The%20entry%20point%20is%20zProc.%20zProc%20may%20be%200 | ||
| entrypoint = "0" | ||
| } */ | ||
| if path == "" { | ||
| return errors.New("the path of the shared object cannot be empty") | ||
| } | ||
| if n.registered { | ||
| return errors.New("the namespace is already registered. Shared extension must be loaded before registering the namespace") | ||
| } | ||
| n.sharedObjectToLoad = append(n.sharedObjectToLoad, sharedObjectExtension{entryPoint: entrypoint, path: path}) | ||
| return nil | ||
| } | ||
|
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| // Register a plugin written in Go built for anyquery for each table of the manifest | ||
| // | ||
| // In the manifest, any zeroed string of table name will be ignored | ||
| func (n *Namespace) LoadAnyqueryPlugin(path string, manifest rpc.PluginManifest, userConfig map[string]string) error { | ||
| if path == "" { | ||
| return errors.New("the path of the plugin cannot be empty") | ||
| } | ||
| if n.registered { | ||
| return errors.New("the namespace is already registered. Anyquery plugin must be loaded before registering the namespace") | ||
| } | ||
|
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| // Load the plugin | ||
| for index, table := range manifest.Tables { | ||
| plugin := &module.SQLiteModule{ | ||
| PluginPath: path, | ||
| PluginManifest: manifest, | ||
| TableIndex: index, | ||
| UserConfig: userConfig, | ||
| } | ||
| n.LoadGoPlugin(plugin, table) | ||
| } | ||
| return nil | ||
| } | ||
|
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| // Register registers the namespace to the database/sql package | ||
| // | ||
| // It takes the name of the connection to register. If not specified, a random name will be generated | ||
| func (n *Namespace) Register(registerName string) (*sql.DB, error) { | ||
| if n.registered { | ||
| return nil, errors.New("the namespace is already registered") | ||
| } | ||
|
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| // Check if the connection string is not empty | ||
| if n.connectionString == "" { | ||
| return nil, errors.New("the connection string cannot be empty. You must init the namespace before registering it") | ||
| } | ||
|
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| // Check if the register name is empty | ||
| if registerName == "" { | ||
| registerName = "anyquery_custom" + strconv.Itoa(rand.Int()) | ||
| } | ||
|
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| for _, driver := range sql.Drivers() { | ||
| if driver == registerName { | ||
| return nil, errors.New("the connection string is already registered") | ||
| } | ||
| } | ||
|
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| // Register the database/sql package | ||
| sql.Register(registerName, &sqlite3.SQLiteDriver{ | ||
| ConnectHook: func(conn *sqlite3.SQLiteConn) error { | ||
|
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| // We load the shared objects | ||
| for _, sharedObject := range n.sharedObjectToLoad { | ||
| err := conn.LoadExtension(sharedObject.path, sharedObject.entryPoint) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| } | ||
|
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| // We load the Go plugins | ||
| for _, goPlugin := range n.goPluginToLoad { | ||
| err := conn.CreateModule(goPlugin.name, goPlugin.plugin) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| } | ||
|
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| return nil | ||
| }, | ||
| }) | ||
|
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| // Create the DB connection | ||
| db, err := sql.Open(registerName, n.connectionString) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| // go-sqlite3 is not thread-safe for writing | ||
| db.SetMaxOpenConns(1) | ||
|
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| n.registered = true | ||
|
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| return db, nil | ||
|
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| } | ||
|
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| func (n *Namespace) GetConnectionString() string { | ||
| return n.connectionString | ||
| } |
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